The invention relates to control lever assembly for generating signals as a function of the position of a manually operable lever.
Increasingly, electrohydraulic valves are being used on agricultural vehicles, such as tractors, to operate various vehicle or implement hydraulic functions. New operator input devices are needed to take advantage of the capabilities of such electrohydraulic valves. Various designs have been proposed in attempts to solve this problem. For example, U.S. Pat. No. 4,419,907, issued 13 Dec. 1983 to Baxter et al., U.S. Pat. No. 4,440,040, issued 3 Apr. 1984 to Kittle et al. and U.S. Pat. No. 4,438,660, issued 27 Mar. 1984 to Kittle, all assigned to the assignee of the present application, show various types of multiple mode control lever assemblies. However, a less complex and less costly lever operated device is desired. Also desired is such a device which can generate output signals which vary linearly as a function of the position of the device within a certain range of positions, which can generate output signals which vary in a step-wise manner in response to a predetermined motion of the device, and which provides tactile feedback to an operator depending on the position of the device and indicative of the character of the output signals being generated. Also desired is such a device which provides a smooth and uniform lever movement within a certain range, which provides a stepwise increase in resistance to lever movement outside of such a range, which requires lever movement in a different direction to move the lever outside of such a range and which provides a detent function to releasably hold the lever in a certain position. Such a lever can provide tactile feedback to make an operator aware of the functional status of the lever and the hydraulic function controlled thereby.